When I bought this "Chinese herbal" beverage (20 baht), as the stall-owner described it, I expected that after-hours web research would pin down the main ingredient. I'll bet that's it, to the left of the only label, but I don't have a substantially clearer photo, and as of this writing the only English-language web mentions of "jub-lieng" are my own. Do any Eating In Translation readers have a clue?
Drinks vendor
Aw Taw Gaw market, stall 12/1, Bangkok